Defer setup to avoid module import-time side-effects

pimoroni / phat-beat

Python library for PHAT BEAT - A stereo DAC, AMP and VU for the Raspberry Pi

https://shop.pimoroni.com/products/phat-beat

MIT License

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Defer setup to avoid module import-time side-effects #14

Closed Gadgetoid closed 6 years ago

Gadgetoid commented 7 years ago

This PR makes several "friendly neighbour" changes to the pHAT BEAT library:

Do not perform any module setup on import
Do not output any messages/text on import
Use ImportError instead of hard exit() for "friendly" import error messages

See here for details of the problems import-time side-effects can have: https://www.raspberrypi.org/forums/viewtopic.php?f=32&t=193502&p=1212488#p1212488

Gadgetoid commented 6 years ago

Needs to drop ensure_setup() and just have setup() set an _is_setup flag and not run any of the actual setup routines twice. The current method is unnecessarily convoluted.